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Mcrid · 11-27-2015, 09:02 AM

Having this SB done today. I understand the only advantage is it eliminates the parasitic current draw by the inverter when the unit is being stored.

UKDUDE · 11-27-2015, 09:20 AM

Good information, Mcrider. Thanks.
Lew, do you know anything about this? Does this mean we should be careful NOT to use the disconnect when plugged into shore power since the Magnum needs to be on?
Peter

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c21 · 11-27-2015, 10:56 AM

I had the same question and I'm not sure this SB would help me as I am either plugged in or operating on solar short term with my battery disconnect on so my frige and fantastic fan can run. Seems like this would benefit those who stored longer term while not plugged in. Also my VIN doesn't fall in the stated VIN range although my unit is in the stated date range.

Protagonist · 11-27-2015, 12:41 PM

Quote:

Originally Posted by UKDUDE

Does this mean we should be careful NOT to use the disconnect when plugged into shore power since the Magnum needs to be on?

No. Part of the existing problem is that the inverter/charger is wired in parallel to the 12v system, and so is still on even when the main disconnect is off. Meaning it doesn't matter whether you have the disconnect on or off when plugged into shore power for storage. In fact, the new solenoid is only essential if you store then van without plugging into shore power. If you hook up to shore power, you'd want to leave the new solenoid on all the time, but the 12v disconnect could be in any position.

If the inverter was shut off by the main disconnect, the new solenoid would not be needed. With the new solenoid you have a way to shut off the inverter/charger without performing vehicular surgery to reach the switch on the back of the Magnum unit. With both the main disconnect and the inverter solenoid turned off, plugging into shore power does nothing anymore, but you still have solar to keep the batteries charged.

UKDUDE · 11-27-2015, 01:18 PM

Quote:

Originally Posted by Protagonist

No. Part of the existing problem is that the inverter/charger is wired in parallel to the 12v system, and so is still on even when the main disconnect is off. Meaning it doesn't matter whether you have the disconnect on or off when plugged into shore power for storage. In fact, the new solenoid is only essential if you store then van without plugging into shore power. If you hook up to shore power, you'd want to leave the new solenoid on all the time, but the 12v disconnect could be in any position.

If the inverter was shut off by the main disconnect, the new solenoid would not be needed. With the new solenoid you have a way to shut off the inverter/charger without performing vehicular surgery to reach the switch on the back of the Magnum unit. With both the main disconnect and the inverter solenoid turned off, plugging into shore power does nothing anymore, but you still have solar to keep the batteries charged.

I'm not sure I fully understand you, Protag, but here's a scenario as an example:
At home it's plugged into shore power. But if I visit friends for a few days and have no need for fridge, etc, so the coach electrics will be in disconnect mode. I drive home and plug in and forget to undo the disconnect. Will the Magnum still do its stuff?

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Mcrid · 11-27-2015, 03:17 PM

After reading Protagonist's post, I went out and tested several configurations. My conclusion is as follows. The SB relay does not impact the Magnum's battery charging when the Main Disconnect switch is off. The Magnum continues to charge (indiated by the LED Status light). In otherwords, the Magnum stays in it's Standby Mode.

I'm infering from my test (without removing the jump seat to trace wiring) that the relay disconnects the 120 VAC Inverter output. This prevents the Magnum from seeing any load (i.e. it's Search Mode) and starting the inverter to produce 120 VAC. According the Owner's Manual, if the Magnum sees a minimum of 5 Watt load it will start the inverter.

So my conclusion is that you can have the Main Disconnect Switch in the off position and as long as shore power the Magnum will still charge.

Hope this helps

lewster · 11-27-2015, 04:19 PM

This is the first I have seen of the SB (not being an authorized Airstream service center). I educate ALL of my clients to keep the inverter OFF (meaning that there will be NO 120VAC COMING FROM THE BATTERIES THE INVERTER AT ANY TIME) and to only put the inverter to the 'ON' position when 120VAC is desired when off-grid and then to immediately TURN OFF THE INVERTER.

This will remove any parasitic draw from the inverter as it searched for the minimum 5 watt load. It has NO EFFECT on the charging section of the Magnum when shore power is present.

I also add a 300 amp marine disconnect switch and a proper class T fuse into the positive DC cable running between the battery and the Magnum positive terminal. This allows for the total isolation of the inverter during off-grid storage and also allows for the required protection of the cable from a potential 10,000 amp transient short; something that the ANL fuse that Airstream provides will not approach but a situation that is entirely possible.

UKDUDE · 11-27-2015, 04:45 PM

Ah yes, all makes sense now. Thanks guys!

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c21 · 11-27-2015, 05:06 PM

Quote:

Originally Posted by lewster

This is the first I have seen of the SB (not being an authorized Airstream service center). I educate ALL of my clients to keep the inverter OFF (meaning that there will be NO 120VAC COMING FROM THE BATTERIES THE INVERTER AT ANY TIME) and to only put the inverter to the 'ON' position when 120VAC is desired when off-grid and then to immediately TURN OFF THE INVERTER.

This will remove any parasitic draw from the inverter as it searched for the minimum 5 watt load. It has NO EFFECT on the charging section of the Magnum when shore power is present.

I also add a 300 amp marine disconnect switch and a proper class T fuse into the positive DC cable running between the battery and the Magnum positive terminal. This allows for the total isolation of the inverter during off-grid storage and also allows for the required protection of the cable from a potential 10,000 amp transient short; something that the ANL fuse that Airstream provides will not approach but a situation that is entirely possible.

Sounding like one could just skip having this extra solenoid installed as it really doesn't add anything that the Magnum doesn't already take care of. Am I correct or still missing something?
Bill

Protagonist · 11-27-2015, 06:09 PM

Quote:

Originally Posted by c21bill

Sounding like one could just skip having this extra solenoid installed as it really doesn't add anything that the Magnum doesn't already take care of. Am I correct or still missing something?
Bill

Do you always store your Interstate with shore power connected? If so, then you could skip it. If you store it without shore power, you should get the solenoid installed and use it to shut off the inverter.

c21 · 11-27-2015, 06:15 PM

Quote:

Originally Posted by Protagonist

Do you always store your Interstate with shore power connected? If so, then you could skip it. If you store it without shore power, you should get the solenoid installed and use it to shut off the inverter.

Sounds like what Lew is saying is that if you turn off the inverter at the remote panel it has the same effect as the solenoid would have with the master switch turned off. In other words, no draw from the inverter.

lewster · 11-27-2015, 08:35 PM

Quote:

Originally Posted by c21bill

Sounds like what Lew is saying is that if you turn off the inverter at the remote panel it has the same effect as the solenoid would have with the master switch turned off. In other words, no draw from the inverter.

According to the MMS-1012 manual, the no load draw for this inverter/charger is 19 watts, or about 1.5 amps DC coming from your batteries. If the inverter function is OFF at the ME-MR control panel, you should see no idling amperage draw, as the inverter function is now off and the charger section is also off when no shore power is present.

Seems like a very simple solution. If you can turn on a solenoid to disconnect the inverter function, why not simply do it from the provided control panel???

BTW, I much prefer the ME-RC remote to the very basic ME-MR that Airstream provides.

And speaking of Airstream, I have a limited supply of ME-BTS battery temp sensors (the ones that Airstream refused to install for a few years on the AI) available for a 'give away' price. PM me for more details.

c21 · 11-27-2015, 08:49 PM

Quote:

Originally Posted by lewster

According to the MMS-1012 manual, the no load draw for this inverter/charger is 19 watts, or about 1.5 amps DC coming from your batteries. If the inverter function is OFF at the ME-MR control panel, you should see no idling amperage draw, as the inverter function is now off and the charger section is also off when no shore power is present.

Seems like a very simple solution. If you can turn on a solenoid to disconnect the inverter function, why not simply do it from the provided control panel???

BTW, I much prefer the ME-RC remote to the very basic ME-MR that Airstream provides.

And speaking of Airstream, I have a limited supply of ME-BTS battery temp sensors (the ones that Airstream refused to install for a few years on the AI) available for a 'give away' price. PM me for more details.

That's exactly what I thought you we're saying before. I'll skip having the solenoid installed as I always prefer less folks working on my unit. BTW I also installed the ME-RC when I upped my solar capacity. I also installed the temp sensor for the Magnum.

Thanks,
Bill

369goose · 11-28-2015, 12:16 PM

How/where can owners learn about these service bulletins? Seems we used to get them when our trailer was brand new.

jim.waters · 11-30-2015, 09:18 AM

This solenoid should correct the problem I have been having. The explanation makes sense for why the drain has been difficult to find. My van falls in the date range of the SB, but the VIN does not look anything like mine. Is the VIN an Airstream number rather than Mercedes? Where does it appear on the vehicle?

Protagonist · 11-30-2015, 09:24 AM

Quote:

Originally Posted by jim.waters

Is the VIN an Airstream number rather than Mercedes? Where does it appear on the vehicle?

Yes, it's an Airstream number. You should be able to find it on the data plate attached to the base of the driver's seat, visible through the open driver's door, though you might have to lift the seat's skirt to see it; I can't remember if it's behind the skirt or below it.

coder · 11-30-2015, 05:44 PM

Well, this service bulletin is certainly interesting. My 2014 Interstate is one of those with the problem of excessive battery drain. The dealer did not apply this to my van, though, when it was in for service this month. The bulletin was published while the dealer had my van, and the van was in for service specifically to look at the excessive battery draw problem. (The dealer found nothing wrong with my batteries or charging system. But the Interstate still loses a half-volt of charge in a week. That's hard on the batteries.)

This service bulletin calls out the Magnum inverter as the source of a "Battery Draw" problem. Since it is trivially easy to make sure the inverter is off, I wonder what else about the inverter might be the culprit. My charger/inverter is set up the way Airstream recommends, and the dealer has checked my inverter more than once, but I wonder now about the "Search Mode" feature.

Anyway, whatever is wrong with my van, it must not be this, since my van was in for service and they didn't feel this service bulletin was important. I'm working my way through all the steps I've got to follow to use Washington's Motor Home Lemon Law.

jim.waters · 12-01-2015, 01:16 PM

Lewster, with the ME-RC controller can the inverter be shut off to avoid the parasitic 0.5 amp drain in the same way the SB 164 added solenoid will?

lewster · 12-01-2015, 05:13 PM

Yes, there is a button in the lower left marked 'Inverter'. This should always be off until you need 120 VAC power from your batteries when off-grid, then turned on.

It should be returned to 'off' when finished using that appliance.

Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

Sailfast · 12-06-2015, 09:14 PM

Quote:

Originally Posted by lewster

Yes, there is a button in the lower left marked 'Inverter'. This should always be off until you need 120 VAC power from your batteries when off-grid, then turned on.

It should be returned to 'off' when finished using that appliance.

Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

Interesting, our AS is one fitting the SB 164 with a current draw of around 0.4A or 10A per 24 hours. This is with the inverter switch on the lower left in the OFF position, rarely using 120AC.

250W of solar sort of takes care of it for outdoor winter storage so far (what winter?) However, still curious as to the source of the draw.